Enterprise Architecture (EA) is a key tool to help businesses transform themselves to meet changing business challenges. To do so, however, architectural methods must themselves be adapted to focus less on technology per se and more on how these technologies enable the business to survive and thrive over the long term—to be sustainable—in the shifting, uncertain business context. We call this shift to Sustainable Enterprise Architecture (SEA) a “SEA change”. The practice of SEA differs from the usual practice of EA in a number of ways. Sustainable architecting emphasizes the long-term perspective, focusing on how the enterprise can identify and respond effectively to a range of strategic disruptions. It is based on systems thinking; is continuous, iterative, and adaptive; and calls for integrated strategic planning, architecting, governance, and learning. It considers sustainability the primary system quality and organizes other system qualities in support of sustainability. The enterprise’s approach to sustainability is recorded in a formal sustainability architecture, which describes the threats to sustainability in the business context and defines sustainability goals, models, principles, policies, and standards to address them. It pays close attention to strategic resources and the pragmatic integration of societal, economic, and environmental considerations. It recognizes that sustainable architecting is a cultural change, and provides a set of essential checklists to guide that change.